[PATCH v3 18/33] nbd/client-connection: shutdown connection on release

[Vladimir Sementsov-Ogievskiy]

Now, when thread can do negotiation and retry, it may run relatively
long. We need a mechanism to stop it, when user is not interested in
result anymore. So, on nbd_client_connection_release() let's shutdown
the socked, and do not retry connection if thread is detached.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 nbd/client-connection.c | 36 ++++++++++++++++++++++++++----------
 1 file changed, 26 insertions(+), 10 deletions(-)

diff --git a/nbd/client-connection.c b/nbd/client-connection.c
index 002bd91f42..54f73c6c24 100644
--- a/nbd/client-connection.c
+++ b/nbd/client-connection.c
@@ -158,9 +158,13 @@ static void *connect_thread_func(void *opaque)
     uint64_t timeout = 1;
     uint64_t max_timeout = 16;
 
-    while (true) {
+    qemu_mutex_lock(&conn->mutex);
+    while (!conn->detached) {
+        assert(!conn->sioc);
         conn->sioc = qio_channel_socket_new();
 
+        qemu_mutex_unlock(&conn->mutex);
+
         error_free(conn->err);
         conn->err = NULL;
         conn->updated_info = conn->initial_info;
@@ -171,14 +175,20 @@ static void *connect_thread_func(void *opaque)
         conn->updated_info.x_dirty_bitmap = NULL;
         conn->updated_info.name = NULL;
 
+        qemu_mutex_lock(&conn->mutex);
+
         if (ret < 0) {
             object_unref(OBJECT(conn->sioc));
             conn->sioc = NULL;
-            if (conn->do_retry) {
+            if (conn->do_retry && !conn->detached) {
+                qemu_mutex_unlock(&conn->mutex);
+
                 sleep(timeout);
                 if (timeout < max_timeout) {
                     timeout *= 2;
                 }
+
+                qemu_mutex_lock(&conn->mutex);
                 continue;
             }
         }
@@ -186,15 +196,17 @@ static void *connect_thread_func(void *opaque)
         break;
     }
 
-    WITH_QEMU_LOCK_GUARD(&conn->mutex) {
-        assert(conn->running);
-        conn->running = false;
-        if (conn->wait_co) {
-            aio_co_schedule(NULL, conn->wait_co);
-            conn->wait_co = NULL;
-        }
-        do_free = conn->detached;
+    /* mutex is locked */
+
+    assert(conn->running);
+    conn->running = false;
+    if (conn->wait_co) {
+        aio_co_schedule(NULL, conn->wait_co);
+        conn->wait_co = NULL;
     }
+    do_free = conn->detached;
+
+    qemu_mutex_unlock(&conn->mutex);
 
     if (do_free) {
         nbd_client_connection_do_free(conn);
@@ -215,6 +227,10 @@ void nbd_client_connection_release(NBDClientConnection 
*conn)
     if (conn->running) {
         conn->detached = true;
     }
+    if (conn->sioc) {
+        qio_channel_shutdown(QIO_CHANNEL(conn->sioc),
+                             QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
+    }
     do_free = !conn->running && !conn->detached;
     qemu_mutex_unlock(&conn->mutex);
 
-- 
2.29.2